1. Field of the Invention
This invention relates to an inspecting apparatus for measuring sensors mounted on a train which enables one to inspect measuring sensors installed at various positions in a train, such as the measuring sensor for air pressure and the like applied to the brake cylinder, without dismounting them from the train.
2. Description of the Prior Art
As the inspecting apparatus for measuring sensors, such as the sensor for measuring the brake cylinder pressure of a train and the one for measuring the bearing temperature of wheels, the following two organizations are conventionally known.
In the first organization, the train is set in an inactive state in the maintenance shop or shed, and an equivalent input (for example, if the object of inspection is the air pressure sensor, the air pressure generated by a compressor) is applied to the measuring sensor from outside, whereby the sensor is evaluated according to its output. This method is disclosed, for example, in Vol. 53, No. 9 of Mitsubishi Electric Technical Review, on pages 695 to 699 published in 1979.
Referring to the inspection of measuring sensor of brake cylinder pressure installed in the air brake control system of a train, an example of strain gauge is explained below though other methods are known as this kind of pressure sensor such as the method of combining plural air pressure switches and detecting by dividing the pressure into several ranges.
First, when the train to be inspected is in inactive state for periodic inspection or extraordinary inspection, the pressure sensor is dismounted from the train at the maintenance shop or shed, and is mounted on a specified inspection apparatus, and an equivalent air pressure is applied to the measuring sensor from an external compressor to measure. On the other hand, the equivalent air pressure applied to the sensor is measured by a proper standard instrument, such as Bourdon tube. Then by comparing the measured results of the measuring sensor and standard instrument, the measuring sensor dismounted from the train is evaluated.
The second organization relates to a method of inspecting the sensor without dismounting it from the train, for example, as disclosed in Vol. 43, No. 11 of Mitsubishi Electric Technical Review, on pages 1504 to 1510 published in 1969.
When inspecting the pressure sensor of Brake cylinder installed in the air brake control system in a train by this method, an equivalent air pressure is supplied to this brake control system from outside, while a proper standard instrument, such as Bourdon Tube, is attached to the same air brake control system. Then by comparing the results measured by the measuring sensor to be inspected and the standard instrument, the measuring sensor is evaluated.
As the conventional inspecting apparatus for measuring sensor mounted on a train is thus organized, various problems are involved.
In the first method, when the measuring sensor to be inspected is dismounted from the train, the peripheral devices and parts must also be removed, and they must be reassembled when the sensor is remounted onto the train. It means there is a risk of misalignment in remounting and assembling the parts as well as in adjusting peripheral devices. Specifically, when inspecting the brake cylinder pressure sensor of air brake control system as described in the above example, air may escape through the piping, or dust may invade into the piping. Furthermore, the measuring sensor to be inspected itself may be injured or deviated in adjustment.
Besides, as the problem common to both methods, the inspection requires external devices for feeding equivalent outputs into to the measuring sensor to be inspected, such as an air compressor, and the devices for receiving the outputs of the measuring sensor to be inspected, such as a voltmeter, and also standard measuring means as a means of comparison. Therefore, it is possible to inspect only in particular maintenance shop or shed fully equipped with those devices, and it is hard to improve the efficiency of inspection, and it is also difficult to shorten the downtime of the train.